Magnetic resonance imaging method, apparatus, computer equipment and storage medium

Abstract

The present application relates to a magnetic resonance imaging method, apparatus, computer device, and storage medium. The method comprises: providing multiple magnetic resonance lamellae based on a target magnetic resonance slice, wherein the combined thickness of the multiple magnetic resonance lamellae is greater than or equal to the thickness of the target magnetic resonance slice; sequentially applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each magnetic resonance lamellae to obtain echo signals corresponding to each magnetic resonance lamellae; and obtaining a target magnetic resonance image based on the echo signals corresponding to each magnetic resonance lamellae. This method can suppress magnetic susceptibility artifacts while also reducing the scanning time of the subject being examined.

Description

Technical Field

[0001] The present application relates to the field of magnetic resonance imaging technology, and in particular to a magnetic resonance imaging method, apparatus, computer equipment, and storage medium. Background Art

[0002] Magnetic resonance imaging (MRI) can reveal multiple tissue properties, including longitudinal relaxation time (T1), transverse relaxation time (T2), and proton density, providing excellent soft tissue contrast. MRI has become a crucial technique for medical imaging. However, MRI places high demands on the uniformity of the main magnetic field (also known as the B0 field). When differences in the magnetic susceptibility of various implants (such as artificial joints, stents, and orthopedic fixation devices) cause localized B0 field inhomogeneities, this can lead to significant signal accumulation or loss in certain areas of the image, as well as image distortion.

[0003] Conventional techniques, such as conventional spin echo (SE) and fast spin echo (FSE), are typically used to minimize image artifacts caused by differences in the magnetic susceptibility of implants. Alternatively, SE-based slice encoding for metal artifact correction (SEMAC) or multi-acquisition variable-resonance image combination (MARVIC) techniques are employed to further suppress susceptibility artifacts through multi-frequency spectral excitation combined with 3D spatial encoding for magnetic resonance imaging.

[0004] However, the traditional magnetic susceptibility suppression method has the problem of long scanning time. Summary of the Invention

[0005] Based on this, it is necessary to provide a magnetic resonance imaging method, apparatus, computer equipment and storage medium that can suppress magnetic susceptibility artifacts while reducing scanning time to address the above technical problems.

[0006] A magnetic resonance imaging method, comprising:

[0007] Arranging a plurality of magnetic resonance thin layers according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0008] applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices in sequence to obtain an echo signal corresponding to each of the magnetic resonance thin slices;

[0009] A target magnetic resonance image is obtained according to the echo signals corresponding to each of the magnetic resonance thin slices.

[0010] In one embodiment, obtaining a target magnetic resonance image according to the echo signals corresponding to each magnetic resonance thin layer includes:

[0011] Imaging the echo signals corresponding to the magnetic resonance thin slices to obtain magnetic resonance sub-images corresponding to the magnetic resonance thin slices;

[0012] The magnetic resonance sub-images are merged to obtain the target magnetic resonance image.

[0013] In one embodiment, the thickness of the magnetic resonance thin layer is determined by:

[0014] The thickness of the magnetic resonance slice is determined according to the thickness of the target magnetic resonance slice and a gradient threshold.

[0015] In one embodiment, before sequentially applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices to obtain an echo signal corresponding to each of the magnetic resonance thin slices, the method further comprises:

[0016] At least one auxiliary pulse of a target frequency is applied to each of the magnetic resonance slices; the spectrum range of the target frequency deviates from the center frequency of the magnetic resonance imaging system.

[0017] In one embodiment, imaging the echo signals corresponding to the magnetic resonance thin slices to obtain magnetic resonance sub-images corresponding to the magnetic resonance thin slices includes:

[0018] using radio frequency pulses to simultaneously excite two magnetic resonance thin layers in each of the magnetic resonance thin layers;

[0019] Simultaneously, different phase modulations are applied to two magnetic resonance thin slices along the phase encoding direction to obtain K-space data;

[0020] The K-space data is reconstructed to obtain magnetic resonance sub-images corresponding to each magnetic resonance thin layer.

[0021] A magnetic resonance imaging method, comprising:

[0022] obtaining a scout image of the scanned object;

[0023] Selecting a range to be scanned on the scout image; the range to be scanned includes a plurality of target magnetic resonance slices;

[0024] For each target MRI slice:

[0025] Applying the scanning sequence multiple times to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of the combined thin layers is greater than or equal to the thickness of the target magnetic resonance slice;

[0026] The multiple magnetic resonance sub-images are weighted to obtain a magnetic resonance image of each target magnetic resonance slice.

[0027] In one embodiment, the method further comprises:

[0028] Before applying the scanning sequence, one or more auxiliary pulses are applied to each target magnetic resonance slice; the frequency of the auxiliary pulses is higher than the frequency of the radio frequency pulses or lower than the frequency of the radio frequency pulses.

[0029] A magnetic resonance imaging apparatus, comprising:

[0030] a setting module, configured to set a plurality of magnetic resonance thin slices according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin slices after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0031] an acquisition module, configured to sequentially apply a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices to obtain an echo signal corresponding to each of the magnetic resonance thin slices;

[0032] The imaging module is used to obtain a target magnetic resonance image according to the echo signals corresponding to each of the magnetic resonance thin slices.

[0033] A computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0034] Arranging a plurality of magnetic resonance thin layers according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0035] applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices in sequence to obtain an echo signal corresponding to each of the magnetic resonance thin slices;

[0036] A target magnetic resonance image is obtained according to the echo signals corresponding to each of the magnetic resonance thin slices.

[0037] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the following steps:

[0038] Arranging a plurality of magnetic resonance thin layers according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0039] applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices in sequence to obtain an echo signal corresponding to each of the magnetic resonance thin slices;

[0040] A target magnetic resonance image is obtained according to the echo signals corresponding to each of the magnetic resonance thin slices.

[0041] The magnetic resonance imaging method, apparatus, computer device, and storage medium described above can provide multiple magnetic resonance lamellae based on a target magnetic resonance slice, and the combined thickness of the multiple magnetic resonance lamellae is greater than or equal to the thickness of the target magnetic resonance slice. Thus, by sequentially applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each magnetic resonance lamella, the time required to obtain an echo signal corresponding to each magnetic resonance lamella is relatively short, i.e., the scanning time is shortened. This method suppresses magnetic susceptibility artifacts while also reducing the scanning time for the subject being examined. Furthermore, based on the echo signals corresponding to each magnetic resonance lamella, a target magnetic resonance image can be quickly obtained, thereby improving the efficiency of obtaining the target magnetic resonance image. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A diagram of an application environment of a magnetic resonance imaging method according to an embodiment;

[0043] Figure 2 is a schematic flow chart of a magnetic resonance imaging method according to an embodiment;

[0044] Figure 2a FIG1 is a schematic diagram of a magnetic resonance imaging with deformation in a slice selection direction obtained by using the prior art in one embodiment;

[0045] Figure 2b A schematic diagram of the division of a magnetic resonance thin layer in one embodiment;

[0046] Figure 2c A schematic diagram of the division of a magnetic resonance thin layer in another embodiment;

[0047] Figure 2d A schematic diagram of the division of a magnetic resonance thin layer in another embodiment;

[0048] Figure 3 is a schematic flow chart of a magnetic resonance imaging method according to another embodiment;

[0049] Figure 3a A schematic diagram of a scanning sequence used for imaging a thin magnetic resonance layer according to an embodiment;

[0050] Figure 3b In one embodiment, Figure 3a Schematic diagram of magnetic resonance imaging obtained by the scanning sequence shown;

[0051] Figure 4a A schematic diagram of the magnetic resonance pulse spectrum range in one embodiment;

[0052] Figure 4b is a schematic diagram of a magnetic resonance image without applying an auxiliary pulse in one embodiment;

[0053] Figure 4c FIG1 is a schematic diagram of applying magnetic resonance pulses to each magnetic resonance thin layer in one embodiment;

[0054] Figure 4d A schematic diagram of simultaneously exciting two target magnetic resonance slices in one embodiment;

[0055] Figure 4e FIG1 is a schematic diagram of a magnetic resonance image in which an auxiliary pulse is applied in one embodiment;

[0056] Figure 5 is a schematic flow chart of a magnetic resonance imaging method according to an embodiment;

[0057] Figure 6 is a structural block diagram of a magnetic resonance imaging device in one embodiment;

[0058] Figure 7 FIG. 4 is a structural block diagram of a magnetic resonance imaging device in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0060] The magnetic resonance imaging method provided in the embodiment of the present application can be applied to Figure 1 The computer device shown. The computer device includes a processor and a memory connected via a system bus, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of the following method embodiment can be executed. Optionally, the computer device may further include a network interface, a display screen, and an input device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory, wherein the non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal via a network connection. Optionally, the computer device can be a server, a personal computer, a personal digital assistant, or other terminal devices, such as a tablet computer, a mobile phone, etc., or a cloud or remote server. The embodiments of the present application do not limit the specific form of the computer device.

[0061] Magnetic resonance imaging (MRI) provides superior soft tissue contrast compared to CT (computed tomography). A typical MRI system consists of the following components: a magnet, gradient coils, radiofrequency transmit coils, radiofrequency receive coils, a signal processing unit, and an image reconstruction unit. The spin of hydrogen nuclei in the human body can be described as a small magnetic needle. In the strong magnetic field provided by the magnet, the hydrogen nuclei shift from a chaotic thermal equilibrium state to one that is partially aligned with and partially opposed to the main magnetic field. The difference between the two forms the net magnetization vector, and the hydrogen nuclei precess around the main magnetic field. The precession frequency is proportional to the magnetic field strength. The gradient unit generates a magnetic field whose intensity varies with spatial position, used for spatial encoding of signals. The RF transmitting coil flips the hydrogen nuclei from the main magnetic field to the transverse plane, causing them to precess around the main magnetic field. This induces a current signal in the RF receiving coil, which then passes through the signal processing unit and image reconstruction unit to produce an image of the tissue being imaged. The MRI system selectively excites the hydrogen atoms in space by controlling the gradient system in a temporal manner, performing spatial encoding. Only when a sufficient amount of spatially encoded signals is collected by the receiving coil can an image be reconstructed. MRI has very high requirements for the uniformity of the main magnetic field (also known as the B0 field). When differences in the magnetic susceptibility of various implants (such as artificial joints, stents, orthopedic internal fixation devices, etc.) cause local B0 field inhomogeneities, this can lead to significant accumulation or loss of local signals in the image, as well as image distortion. Conventional techniques typically use self-selected echo sequences (such as SE and FSE) to minimize image artifacts caused by differences in the magnetic susceptibility of implants. Alternatively, SEMAC (interslice coded metal artifact correction) or MARVIC techniques based on SE sequences are employed to further suppress magnetic susceptibility artifacts through multi-spectral excitation combined with 3D spatial encoding for magnetic resonance imaging. However, the use of multi-spectral excitation and 3D encoding significantly increases scan times beyond those of conventional clinical imaging, leading to longer scan times. Therefore, there is a need for a magnetic resonance imaging method, apparatus, computer device, and storage medium that can suppress magnetic susceptibility artifacts while reducing scan times.

[0062] In one embodiment, Figure 2 As shown, a magnetic resonance imaging method is provided, which is applied to Figure 1 The computer device in the example is used to illustrate the process, including the following steps:

[0063] S201 , providing a plurality of magnetic resonance thin slices according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin slices after combination is greater than or equal to the thickness of the target magnetic resonance slice.

[0064] In this embodiment, the thickness of the combined MRI slices is greater than or equal to the thickness of the target MRI slice. That is, the imaging range of the combined MRI slices along the slice combination / thickness direction is greater than or equal to the imaging range of the target MRI slice. In this embodiment, a "MRI slice" may also be referred to as a "slice subdivision layer" or "slice segmentation layer," and each MRI slice can be used for two-dimensional slice imaging. It should be noted that a major manifestation of magnetic susceptibility artifacts in two-dimensional MRI imaging is distortion in the slice selection direction. Figure 2a The magnetic resonance image is obtained by scanning the scan object using the existing technology, which uses the scanning sequence to directly excite the target magnetic resonance slice. A metal implant (black wedge in the figure) is set in the target magnetic resonance slice of the scan object. The metal implant will cause the local B0 field to be uneven, and the magnetic resonance image of the target magnetic resonance slice will have a spike-like artifact at the metal implant. Specifically, the spike-like artifact is caused by the unevenness of the local B0 field superimposed on the slice selection gradient, which causes the position of the radio frequency pulse excitation to deviate. When the slice selection gradient used is larger, the deviation of the excitation slice position caused by the local B0 field unevenness is smaller, and the deformation of the image slice selection direction is smaller. Usually, the slice selection gradient G ss The size of is given by the formula:

[0065]

[0066] Calculated, where f rf is the excitation bandwidth of the RF pulse, which is limited by the physical indicator of the RF hardware system "maximum B1 field"; T is the thickness of the excitation layer; γ is the gyromagnetic ratio, which is usually a constant. It can be seen that the size of the layer selection gradient is not only limited by the physical indicator of the gradient hardware system "maximum gradient field Gmax", but also by the physical indicator of the RF hardware system "maximum B1 field". Therefore, in order to make the layer selection gradient as large as possible, in addition to increasing the excitation bandwidth of the RF pulse, it can also be achieved by reducing the thickness of the excitation layer and performing thin layer scanning, that is, multiple thin layers can be divided in the conventional imaging layer, and the largest possible layer selection gradient G' can be obtained by exciting and scanning these thin layers. ss , thus ensuring that the deformation in the layer direction is as small as possible.

[0067] Specifically, the computer device can determine the thickness of the magnetic resonance thin layer according to the thickness of the target magnetic resonance slice. Optionally, in this embodiment, the computer device can determine the thickness of the magnetic resonance thin layer according to the size of the slice selection gradient. For example, the conventional target magnetic resonance slice can be divided into thin layers as follows: Figure 2bAs shown, each conventional target magnetic resonance slice can be divided separately. The target magnetic resonance slice 1 is divided into four thin layers (thin layer 1-thin layer 4) arranged adjacent to each other in sequence, and the imaging range of the combination of thin layers 1-thin layer 4 along the thickness direction is equal to the range of the target magnetic resonance slice 1; the target magnetic resonance slice 2 is divided into four thin layers (thin layer 5-thin layer 8) arranged adjacent to each other in sequence, and the imaging range of the combination of thin layers 5-thin layer 8 along the thickness direction is equal to the range of the target magnetic resonance slice 2.

[0068] If the thickness T of the target magnetic resonance slice is equal to the thickness T of the magnetic resonance thin layer s If the target magnetic resonance slice is not divided evenly, the target magnetic resonance slice is divided into thin slices, which can be done as follows Figure 2c As shown, the imaging range of the combination of thin layers 1-4 along the thickness direction is larger than the range of the target magnetic resonance slice 1, and the imaging range of the combination of thin layers 5-8 along the thickness direction is larger than the range of the target magnetic resonance slice 2. More specifically, thin layers 1-3 are completely within the range of the target magnetic resonance slice 1, and thin layer 4 is only T thick. s1 thin layers 5-7 are completely within the scope of the target magnetic resonance slice 2, and thin layer 8 is only partially within the scope of the target magnetic resonance slice 2.

[0069] If there is no inter-slice gap between conventional target MRI slices, Figure 2d As shown, for two adjacent target MRI slices, the range covered by all conventional slices is considered as a whole and thin slices are divided. The imaging range of the combination of slices 1 to 7 along the thickness direction is larger than the combined range of target MRI slices 1 and 2. More specifically, slices 1-3 are completely within the range of target MRI slice 1, and the thickness of slice 4 is T s1 The portion is located within the range of the target magnetic resonance slice 1, and the thickness of the thin layer 4 is T s2 The thin layer 5 and 6 are completely within the range of the target magnetic resonance layer 2, and the thin layer 7 is only T thick. s3 The portion of the target magnetic resonance slice 2 is located within the range of the target magnetic resonance slice. In this embodiment, if the range of the thin slice exceeds the range of the corresponding conventional slice, the signal contribution of the excess portion is eliminated during the thin slice merging process. In the embodiment of the present application, the thickness of each thin slice is divided into the same thickness. It is understandable that the present application does not impose any specific restrictions on the thickness division form of each thin slice. The thin slices of the same target magnetic resonance slice can also be set to different thicknesses. The thickness of each thin slice only needs to satisfy formula (1).

[0070] S202 , applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each magnetic resonance thin slice in sequence to obtain an echo signal corresponding to each magnetic resonance thin slice.

[0071] Specifically, the computer device controls the magnetic resonance imaging device to apply the slice selection gradient, phase encoding gradient and readout gradient to each of the above-mentioned magnetic resonance thin slices in sequence to obtain the echo signal corresponding to each magnetic resonance thin slice. Optionally, the intensity G' of the slice selection gradient applied in this embodiment is ss Not less than 15 mT / m. Optionally, while controlling the MRI device to apply readout gradients to each of the aforementioned MRI slices, the computer device can also control the MRI device to apply an additional slice selection gradient in the slice selection direction to alleviate distortion along the slice direction and suppress magnetic susceptibility artifacts caused by B0 field inhomogeneity in the slice selection direction. Optionally, the computer device can further increase the readout bandwidth when reading the echo signals corresponding to each MRI slice.

[0072] S203 , obtaining a target magnetic resonance image according to the echo signals corresponding to each magnetic resonance thin slice.

[0073] Specifically, the computer device obtains a target magnetic resonance image based on the echo signals corresponding to each magnetic resonance thin layer obtained above. Optionally, the computer device can image the echo signals corresponding to each magnetic resonance thin layer, and obtain the target magnetic resonance image based on the imaging of each magnetic resonance thin layer. Optionally, when imaging each magnetic resonance thin layer, the computer device can select multiple slice selection gradients in conjunction with corresponding radio frequency pulses to excite the thin layer. Optionally, the intensity difference between the selected multiple slice selection gradients is no more than 5 mT / m. For example, taking the target magnetic resonance slice corresponding to 30 magnetic resonance thin layers as an example, when imaging these 30 magnetic resonance thin layers, the computer device can simultaneously excite the first magnetic resonance thin layer and the 16th magnetic resonance thin layer for the first time, and simultaneously excite the second magnetic resonance thin layer and the 17th magnetic resonance thin layer for the second time, and so on, sequentially, until all 30 magnetic resonance thin layers have been excited 15 times.

[0074] In the aforementioned MRI methods, the number of thin slices divided in the target MRI slice determines the length of the scan time. However, in the SEMAC and MARVIC methods, the scan time is determined by the number of inter-slice codes and the number of frequency spectra. Typically, the number of thin slices in this method is far less than that in the other two methods. Therefore, the target MRI image can be obtained relatively quickly while suppressing magnetic susceptibility artifacts, thereby improving the scanning speed.

[0075] In this embodiment, the computer device can set multiple magnetic resonance slices based on the target magnetic resonance slice, and the thickness of the multiple magnetic resonance slices combined is greater than or equal to the thickness of the target magnetic resonance slice. In this way, the slice selection gradient, phase encoding gradient, and readout gradient are sequentially applied to each magnetic resonance slice. The time to obtain the echo signal corresponding to each magnetic resonance slice will be relatively short, that is, the scanning time is shortened. Therefore, this method suppresses magnetic susceptibility artifacts while also reducing the scanning time of the subject to be examined. In addition, based on the echo signals corresponding to each magnetic resonance slice, the target magnetic resonance image can be quickly obtained, thereby improving the efficiency of obtaining the target magnetic resonance image.

[0076] In the above scenario of obtaining a target magnetic resonance image based on the echo signals corresponding to each magnetic resonance thin layer, in one embodiment, Figure 3 As shown, the above S203 includes:

[0077] S301 , imaging the echo signals corresponding to each magnetic resonance thin slice to obtain a magnetic resonance sub-image corresponding to each magnetic resonance thin slice.

[0078] Specifically, the computer device images the echo signals corresponding to each of the magnetic resonance lamellae to obtain a magnetic resonance subimage corresponding to each magnetic resonance lamellae. Optionally, the computer device can control the magnetic resonance imaging device to simultaneously excite two magnetic resonance lamellae in each magnetic resonance lamellae using radio frequency pulses, while simultaneously applying different phase modulations to the two magnetic resonance lamellae along the phase encoding direction to acquire K-space data, and reconstruct the K-space data to obtain a magnetic resonance subimage corresponding to each magnetic resonance lamellae. Optionally, the computer device can use any one of a parallel imaging acceleration imaging method, a compressed sensing acceleration imaging method, or a half-Fourier acceleration imaging method to image the excited magnetic resonance lamellae to obtain a magnetic resonance subimage corresponding to each magnetic resonance lamellae.

[0079] like Figure 3a As shown, Figure 3a Schematic diagram of the scanning sequence used for imaging a thin magnetic resonance layer in one embodiment of the present application. RF represents the radio frequency pulse excited by the radio frequency coil; G ss G represents the slice selection gradient field formed by applying gradient pulses to the gradient coil; PE G represents the phase encoding selection gradient field formed by applying gradient pulses to the gradient coil; ROrepresents the readout encoding gradient field formed by applying gradient pulses to the gradient coil; Echo represents the magnetic resonance signal generated by excitation of the magnetic resonance thin slice. In this embodiment, a slice selection gradient g1 is applied simultaneously with the 90° RF pulse excitation; a refocusing pulse of α° is then applied, and a slice selection gradient g2 is applied simultaneously with the refocusing pulse. A phase encoding gradient g3 (with varying pulse amplitudes at different times) and a readout encoding gradient g4 are then applied, thereby acquiring the magnetic resonance signals (e1-e4) generated by excitation of the magnetic resonance thin slice. In this embodiment, after the readout encoding gradient g4 is applied, an additional slice selection gradient g5 is applied as a compensation gradient. The amplitude of this compensation gradient can be consistent with the amplitude of the slice selection gradient during 90° RF pulse excitation to suppress chemical shift and metal artifacts caused by magnetic field inhomogeneity. In this embodiment, the amplitude of the slice selection gradient g2 applied simultaneously with the refocusing pulse is set to equal the gradient threshold to ensure that the deformation in the slice direction is minimized.

[0080] S302: Merge the magnetic resonance sub-images to obtain a target magnetic resonance image.

[0081] Specifically, the computer device merges the magnetic resonance sub-images obtained above to obtain the target magnetic resonance image. For example, before merging the magnetic resonance sub-images, the magnetic resonance thin-slice signals SS are first determined. i For the target magnetic resonance slice S j Contribution weight W ij , where i is the number of the target magnetic resonance slice divided by the target magnetic resonance slice and is a positive integer, j is the number of the target magnetic resonance slice and is a positive integer, and i ≥ j. If any magnetic resonance slice is completely contained in the slice range, then W ij =1; if the magnetic resonance thin layer is partially contained within the target magnetic resonance slice range, then W ij is equal to the ratio of the thickness of the magnetic resonance thin layer contained in the target magnetic resonance slice to Ts; if the magnetic resonance thin layer is outside the target magnetic resonance slice range, then W ij Equal to 0.

[0082] Please refer to Figure 2c The thickness of the four magnetic resonance thin layers corresponding to the target magnetic resonance slice 1 are all set to T s If the magnetic resonance thin layers 1 to 3 are completely within the range of the target magnetic resonance slice 1, the corresponding contribution weight is set to 1.0; the thickness of the magnetic resonance thin layer 4 within the range of the target magnetic resonance slice 1 is T s1 , then its contribution is set to T s1 / T s .

[0083] Please continue to refer to Figure 2d, the target magnetic resonance slices 1 and 2 are divided into 7 magnetic resonance slices. Among them, the contribution of magnetic resonance slices 1 to 3 to the target magnetic resonance slice 1 is equal to 1.0; the contribution of magnetic resonance slice 4 to the target magnetic resonance slice 1 is set to T s1 / T s , and the contribution of the magnetic resonance thin layer 4 to the target magnetic resonance slice 2 is set to T s2 / T s ; The contribution of thin magnetic resonance layers 5 to 6 to the target magnetic resonance layer 2 is equal to 1.0; the contribution of thin layer 7 to the target magnetic resonance layer 2 is set to T s3 / T s .

[0084] In the case of multi-coil channel acquisition, the signal of the target magnetic resonance slice can be obtained by the following formula: S j =∑ k ∑ i ((SS ki *W ij )*W ki ), where K represents the coil channel number and is a positive integer; SS ki is the signal size of the magnetic resonance layer i in the kth coil channel; W ki is the weight of the magnetic resonance slice i of the kth channel when the signal is combined. Typically W ki It can be calculated by the root mean square method or the method of adaptive weighting based on signal strength. Figure 3b The magnetic resonance image of the scanned object acquired through multi-channels is shown. This magnetic resonance image can effectively suppress the appearance of spike-shaped artifacts caused by metal implants and suppress the deformation of the image slice selection direction caused by local B0 field inhomogeneity.

[0085] In this embodiment, the computer device images the echo signals corresponding to each magnetic resonance thin layer, and the process of obtaining the magnetic resonance sub-image corresponding to each magnetic resonance thin layer is very simple. In this way, the computer device can quickly obtain the magnetic resonance sub-image corresponding to each magnetic resonance based on the echo signals corresponding to each magnetic resonance thin layer, and then can quickly merge the magnetic resonance sub-images to obtain the target magnetic resonance image, thereby improving the efficiency of obtaining the target magnetic resonance image.

[0086] In the scenario described above where multiple magnetic resonance thin slices are provided based on the target magnetic resonance slice, and the combined thickness of the multiple magnetic resonance thin slices is greater than or equal to the thickness of the target magnetic resonance slice, based on the above embodiment, in one embodiment, the thickness of the magnetic resonance thin slice is determined as follows: the thickness of the magnetic resonance thin slice is determined based on the thickness of the target magnetic resonance slice and a gradient threshold.

[0087] Specifically, the computer device determines the thickness of the magnetic resonance thin layer according to the thickness of the target magnetic resonance slice and the gradient threshold, for example, the thin layer thickness is determined to be 1 / 2 of the target magnetic resonance slice thickness, that is, T s =T / 2, then according to formula (1), it is easy to get the gradient of the excitation layer as G' ss =2G ss , as long as G' ss It is sufficient that the gradient threshold (the maximum gradient field Gmax of the system) is not exceeded. Optionally, the computer device can make full use of the maximum gradient field Gmax of the system to obtain the thinnest layer thickness, that is, G' ss =Gmax, then In this case, the thickness T of the target magnetic resonance slice is equal to the thickness T of the magnetic resonance thin layer. s Not divisible.

[0088] In this embodiment, once the computer device has determined the thickness of the target magnetic resonance slice, it can determine the thickness of the magnetic resonance thin layer based on the thickness of the target magnetic resonance slice and the gradient threshold. This determination process is very simple and reduces the amount of calculation required in determining the thickness of the magnetic resonance thin layer.

[0089] In the scenario described above where a slice selection gradient, a phase encoding gradient, and a readout gradient are sequentially applied to each magnetic resonance lamella to obtain an echo signal corresponding to each magnetic resonance lamella, the computer device may further control the magnetic resonance device to apply at least one radio frequency pulse to each magnetic resonance lamella to suppress signal accumulation caused by a nonuniform B0 field. Based on the above embodiment, in one embodiment, prior to S202, the method further includes: applying at least one auxiliary pulse of a target frequency to each magnetic resonance lamella; the spectral range of the target frequency deviates from the center frequency of the magnetic resonance imaging system.

[0090] Specifically, the computer device controls the magnetic resonance imaging device to apply at least one auxiliary pulse of a target frequency to each of the above-mentioned magnetic resonance thin layers; wherein the spectral range of the target frequency deviates from the center frequency of the magnetic resonance imaging system. Optionally, the computer device can control the magnetic resonance imaging device to apply at least one auxiliary pulse with a spectral range far greater than the center frequency of the magnetic resonance imaging system to each of the above-mentioned magnetic resonance thin layers, or can control the magnetic resonance imaging device to apply at least one auxiliary pulse with a spectral range far less than the center frequency of the magnetic resonance imaging system to each of the above-mentioned magnetic resonance thin layers, or can control the magnetic resonance imaging device to simultaneously apply auxiliary pulses with spectral ranges far greater than and far less than the center frequency of the magnetic resonance imaging system to each of the above-mentioned magnetic resonance thin layers. It can be understood that there is a large degree of non-uniformity in the B0 field in the local area close to the implant, and the resonance frequency of this area is much higher or lower than the center frequency of the system (main magnetic field frequency or radio frequency pulse frequency). As shown in FIG. Figure 4aThis is a schematic diagram of the magnetic resonance pulse spectrum range in an embodiment. On both sides of the system center frequency, there are a fat resonance frequency region, a first interference resonance frequency region (corresponding to the saturation pulse Rf1 spectrum range), and a second interference resonance frequency region (corresponding to the saturation pulse Rf2 spectrum range). The signals in the aforementioned regions are the main source of signal pile-up artifacts on the image. Figure 4b Figure 1 shows a schematic diagram of an MRI image without auxiliary pulses in one embodiment. Signal pile-up artifacts appear in the area indicated by the arrows. Therefore, one or more regional non-selective saturation pulses with a spectral range far from the system frequency and wide enough to effectively cover the resonant frequencies of the B0 field inhomogeneity region can be used to suppress signal generation in that region, thereby reducing the intensity of the signal pile-up artifacts on the image.

[0091] like Figure 4c As shown, the target magnetic resonance slice is divided into N thin slices, where N is an integer greater than 2. Within the repetition time (TR), two saturation pulses Rf1 and Rf2 are applied as auxiliary pulses before the thin slice 1 is excited by the scanning sequence, and the spectrum range of the saturation pulses Rf1 and Rf2 is different from the center frequency of the radio frequency pulse contained in the scanning sequence. Similarly, for thin slices 2 to N, two saturation pulses Rf1 and Rf2 are also applied before each thin slice is excited. Figure 4e As shown, since the spectrum range of the saturation pulses Rf1 and Rf2 is wide enough to effectively cover the resonance frequency region of the B0 field inhomogeneity area, the non-selective saturation pulses suppress the generation of signals in this area, thereby reducing the intensity of signal accumulation artifacts on the image.

[0092] In one embodiment, multiple target magnetic resonance slices can be excited simultaneously. Figure 4d Figure 2 shows a schematic diagram of simultaneously exciting two target magnetic resonance slices in one embodiment. Target magnetic resonance slice 1 is divided into thin slices 1-4, and target magnetic resonance slice 2 is divided into thin slices 5-8. After each scan sequence is executed, both thin slices are excited simultaneously to achieve multi-layer simultaneous excitation. In this embodiment, after the first scan sequence is executed, RF pulses simultaneously excite thin slices 1 and 5, and different phase modulations are simultaneously applied to the different thin slices along the phase encoding direction. After reconstruction, inter-slice separation is achieved. Similarly, RF pulses are sequentially used to simultaneously excite thin slices 2 and 6, thin slices 3 and 7, and thin slices 4 and 8. Different phase modulations are simultaneously applied to the different thin slices along the phase encoding direction. After reconstruction, inter-slice separation is achieved.

[0093] In one embodiment, an undersampling method is also combined in the process of simultaneously exciting two thin layers: a phase-adjustable RF pulse combination is used to perform undersampling to obtain K-space data. For example, the phase of the RF pulse corresponding to thin layer 1 remains fixed (such as 0 degrees), and the phase of the RF pulse corresponding to thin layer 2 is alternately changed by 180 degrees. The K-space data contains the full sampling area, and the combined RF pulse phase corresponding to one sampling data line in the full sampling area is 0 degrees and 0 degrees; the combined RF pulse phase corresponding to another sampling data line in the full sampling area is 0 degrees and 180 degrees. For the sampling data lines in the full sampling area, the data lines with the same phase cycle mode are accelerated separately to obtain K space containing complete data. In the embodiment of the present application, accelerated sampling of multiple thin layers can be achieved simultaneously, thereby improving the sampling speed.

[0094] In this embodiment, a computer device controls a magnetic resonance scanning device to sequentially apply a slice selection gradient, a phase encoding gradient, and a readout gradient to each magnetic resonance slice. Before obtaining an echo signal corresponding to each magnetic resonance slice, an auxiliary pulse having at least one target frequency whose spectral range deviates from the center frequency of the magnetic resonance imaging system is applied to each magnetic resonance slice. This can reduce the intensity of signal pile-up artifacts on the obtained magnetic resonance image and reduce the generation of magnetic resonance artifacts.

[0095] In one embodiment, Figure 5 As shown, a magnetic resonance imaging method is provided, which is applied to Figure 1 The computer device in the example is used to illustrate the process, including the following steps:

[0096] S501, obtaining a positioning image of the scan object.

[0097] Specifically, the computer device acquires a scout image of the scanned object. Alternatively, the computer device may acquire the scout image of the scanned object from the magnetic resonance scanning device in real time via a communication connection with the magnetic resonance scanning device. Alternatively, the computer device may be integrated into the magnetic resonance scanning device, receiving the scout image of the scanned object in real time while the magnetic resonance scanning device is performing a scan.

[0098] S502, selecting a range to be scanned on the scout image; the range to be scanned includes a plurality of target magnetic resonance slices.

[0099] Specifically, the computer device selects a to-be-scanned range on the acquired scout image of the scanned object; wherein the selected to-be-scanned range includes a plurality of target magnetic resonance slices. Optionally, the computer device may determine an artifact-free area on the scout image of the scanned object as the to-be-scanned range.

[0100] S503 , for each target magnetic resonance slice: applying a scanning sequence multiple times to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of the combined thin layers is greater than or equal to the thickness of the target magnetic resonance slice.

[0101] Specifically, the computer controls the magnetic resonance imaging device to apply a scanning sequence multiple times to each target magnetic resonance slice after radio frequency pulse excitation, thereby obtaining multiple magnetic resonance sub-images. Each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the combined thickness of the thin layers is greater than or equal to the thickness of the target magnetic resonance slice. Optionally, after applying multiple slice selection gradients to each target magnetic resonance slice, the computer receives echo signals returned from each target magnetic resonance slice and reconstructs the received echo signals to obtain multiple magnetic resonance sub-images. Optionally, each magnetic resonance sub-image can be reconstructed from the echo signals corresponding to a single target magnetic resonance slice or from the echo signals corresponding to multiple target magnetic resonance slices.

[0102] S504 , performing weighted processing on the multiple magnetic resonance sub-images to obtain a magnetic resonance image of each target magnetic resonance slice.

[0103] Specifically, the computer device performs weighted processing on the multiple magnetic resonance sub-images obtained above to obtain a magnetic resonance image of each target magnetic resonance slice. Optionally, the computer device may perform weighted processing on the multiple magnetic resonance sub-images based on the weights of the multiple magnetic resonance sub-images to obtain a magnetic resonance image of each target magnetic resonance slice.

[0104] In the above-mentioned magnetic resonance imaging method, a computer device obtains a scouting image of the scanned object, selects a range to be scanned including multiple target magnetic resonance slices on the scouting image, and then applies the following multiple times to each target magnetic resonance slice: Figure 3a The slice selection gradient, phase encoding gradient, and frequency encoding gradient shown are used to obtain multiple magnetic resonance sub-images. Each of these multiple magnetic resonance sub-images corresponds to one or more thin layers of the target magnetic resonance slice, and the thickness of the one or more thin layers of the target magnetic resonance slice corresponding to each magnetic resonance sub-image is smaller than the thickness corresponding to the magnetic resonance sub-image. In this way, when scanning the thin layer, the scanning time is shorter, that is, the scanning time is shortened. In addition, the process of weighted processing the multiple magnetic resonance sub-images obtained to obtain the magnetic resonance image of each target magnetic resonance slice is very simple, thereby improving the efficiency of obtaining the magnetic resonance image of the target magnetic resonance slice.

[0105] In the above scenario of applying multiple slice selection gradients, based on the above embodiment, in one embodiment, the above method further includes: before applying the scanning sequence, applying one or more auxiliary pulses to each target magnetic resonance slice; the frequency of the auxiliary pulses is higher than the frequency of the radio frequency pulses or lower than the frequency of the radio frequency pulses.

[0106] Specifically, the computer device controls the magnetic resonance imaging device to apply one or more auxiliary pulses to each target magnetic resonance slice before applying the above-mentioned scanning sequence. The frequency of the auxiliary pulses is higher than or lower than the frequency of the above-mentioned radio frequency pulses. Optionally, the computer device may control the magnetic resonance imaging device to apply one auxiliary pulse having a frequency higher than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying multiple slice selection gradients, or may control the magnetic resonance imaging device to apply multiple auxiliary pulses having a frequency higher than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying multiple slice selection gradients, or may control the magnetic resonance imaging device to apply one auxiliary pulse having a frequency lower than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying multiple slice selection gradients, or may control the magnetic resonance imaging device to apply multiple auxiliary pulses having a frequency lower than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying multiple slice selection gradients, or may control the magnetic resonance imaging device to apply multiple auxiliary pulses having a frequency higher than the frequency of the radio frequency pulse and multiple auxiliary pulses having a frequency lower than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying multiple slice selection gradients.

[0107] In this embodiment, the computer device controls the magnetic resonance scanning device to apply one or more auxiliary pulses with a frequency higher than or lower than the frequency of the radio frequency pulse to each target magnetic resonance slice before applying the scanning sequence. This can reduce the intensity of signal pile-up artifacts on the obtained magnetic resonance image and reduce the generation of magnetic resonance artifacts.

[0108] It should be understood that although Figure 2-5 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 2-5 At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The order of execution of these steps or stages is not necessarily one by one, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0109] In one embodiment, Figure 6As shown, a magnetic resonance imaging device is provided, comprising: a determination module, an acquisition module and an imaging module, wherein:

[0110] The setting module is used to set a plurality of magnetic resonance thin layers according to the target magnetic resonance slice, and the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice.

[0111] The acquisition module is used to apply the slice selection gradient, phase encoding gradient and readout gradient to each magnetic resonance thin layer in sequence to obtain the echo signal corresponding to each magnetic resonance thin layer.

[0112] The imaging module is used to obtain a target magnetic resonance image according to the echo signals corresponding to each magnetic resonance thin layer.

[0113] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0114] Based on the above embodiment, optionally, the imaging module includes: an imaging unit and a merging unit, wherein:

[0115] The imaging unit is used to image the echo signals corresponding to each magnetic resonance thin layer to obtain the magnetic resonance sub-image corresponding to each magnetic resonance thin layer.

[0116] The merging unit is used to merge the magnetic resonance sub-images to obtain a target magnetic resonance image.

[0117] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0118] Based on the above embodiment, optionally, the above setting module includes: a determination unit, wherein:

[0119] The determining unit is configured to determine the thickness of the magnetic resonance thin layer according to the thickness of the target magnetic resonance slice and the gradient threshold.

[0120] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be described in detail here.

[0121] Based on the above embodiment, optionally, the above device further includes: an application module, wherein:

[0122] The applying module is used to apply at least one auxiliary pulse of a target frequency to each magnetic resonance thin layer; the spectrum range of the target frequency deviates from the center frequency of the magnetic resonance imaging system.

[0123] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0124] Based on the above embodiment, optionally, the above imaging unit is specifically used to use radio frequency pulses to simultaneously excite two magnetic resonance thin layers in each magnetic resonance thin layer, and at the same time apply different phase modulations to the two magnetic resonance thin layers along the phase encoding direction to obtain K-space data; reconstruct the K-space data to obtain magnetic resonance sub-images corresponding to each magnetic resonance thin layer.

[0125] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0126] In one embodiment, Figure 7 As shown, a magnetic resonance imaging device is provided, comprising: a first acquisition module, a selection module, a second acquisition module and a third acquisition module, wherein:

[0127] The first acquisition module is used to acquire a positioning image of the scanned object.

[0128] The selection module is used to select a range to be scanned on the positioning image; the range to be scanned includes multiple target magnetic resonance slices.

[0129] The second acquisition module is configured to apply a scanning sequence multiple times to each target magnetic resonance slice to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of the combined thin layers is greater than or equal to the thickness of the target magnetic resonance slice.

[0130] The third acquisition module is configured to perform weighted processing on the multiple magnetic resonance sub-images to obtain a magnetic resonance image of each target magnetic resonance slice.

[0131] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0132] On the basis of the above embodiment, optionally, the above device further includes: an application module, wherein:

[0133] The applying module is used to apply one or more auxiliary pulses to each target magnetic resonance slice before applying the scanning sequence; the frequency of the auxiliary pulses is higher than the frequency of the radio frequency pulses or lower than the frequency of the radio frequency pulses.

[0134] The magnetic resonance imaging device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effects are similar, which will not be repeated here.

[0135] The specific definition of the magnetic resonance imaging apparatus can be found in the definition of the magnetic resonance imaging method above and will not be repeated here. Each module in the magnetic resonance imaging apparatus described above may be implemented in whole or in part through software, hardware, or a combination thereof. Each of the modules described above may be embedded in or independent of a processor in a computer device in hardware form, or may be stored in a computer device memory in software form, so that the processor can call and execute the corresponding operations of each module.

[0136] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0137] Arranging a plurality of magnetic resonance thin layers according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0138] Applying slice selection gradient, phase encoding gradient and readout gradient to each magnetic resonance slice in sequence to obtain the echo signal corresponding to each magnetic resonance slice;

[0139] The target magnetic resonance image is obtained according to the echo signals corresponding to each magnetic resonance thin layer.

[0140] The implementation principle and technical effects of the computer device provided in the above embodiment are similar to those of the above method embodiment and will not be repeated here.

[0141] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0142] Arranging a plurality of magnetic resonance thin layers according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin layers after combination is greater than or equal to the thickness of the target magnetic resonance slice;

[0143] Applying slice selection gradient, phase encoding gradient and readout gradient to each magnetic resonance slice in sequence to obtain the echo signal corresponding to each magnetic resonance slice;

[0144] The target magnetic resonance image is obtained according to the echo signals corresponding to each magnetic resonance thin layer.

[0145] The computer-readable storage medium provided in the above embodiment has similar implementation principles and technical effects to those of the above method embodiment, and will not be described in detail here.

[0146] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0147] obtaining a scout image of the scanned object;

[0148] A range to be scanned is selected on the scout image; the range to be scanned includes a plurality of target magnetic resonance slices;

[0149] For each target MRI slice:

[0150] Applying the scanning sequence multiple times to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of the combined thin layers is greater than or equal to the thickness of the target magnetic resonance slice;

[0151] Weighted processing is performed on the multiple magnetic resonance sub-images to obtain a magnetic resonance image of each target magnetic resonance slice.

[0152] The implementation principle and technical effects of the computer device provided in the above embodiment are similar to those of the above method embodiment and will not be repeated here.

[0153] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0154] obtaining a scout image of the scanned object;

[0155] A range to be scanned is selected on the scout image; the range to be scanned includes a plurality of target magnetic resonance slices;

[0156] For each target MRI slice:

[0157] Applying the scanning sequence multiple times to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of the combined thin layers is greater than or equal to the thickness of the target magnetic resonance slice;

[0158] Weighted processing is performed on the multiple magnetic resonance sub-images to obtain a magnetic resonance image of each target magnetic resonance slice.

[0159] The computer-readable storage medium provided in the above embodiment has similar implementation principles and technical effects to those of the above method embodiment, and will not be described in detail here.

[0160] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0161] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0162] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A magnetic resonance imaging method, characterized in that: The method comprises: Arranging a plurality of magnetic resonance thin slices according to a target magnetic resonance slice, wherein the thickness of the plurality of magnetic resonance thin slices combined is greater than or equal to the thickness of the target magnetic resonance slice, and the thickness of each magnetic resonance thin slice is determined according to the thickness of the target magnetic resonance slice and a gradient threshold; applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices in sequence, and applying an additional compensation gradient in the slice selection direction of each of the magnetic resonance thin slices while applying the readout gradient, to obtain an echo signal corresponding to each of the magnetic resonance thin slices; A target magnetic resonance image is obtained according to the echo signals corresponding to each of the magnetic resonance thin slices.

2. The method according to claim 1, characterized in that Obtaining a target magnetic resonance image according to the echo signals corresponding to each magnetic resonance thin layer includes: Imaging the echo signals corresponding to the magnetic resonance thin slices to obtain magnetic resonance sub-images corresponding to the magnetic resonance thin slices; The magnetic resonance sub-images are merged to obtain the target magnetic resonance image.

3. The method according to claim 1, characterized in that The imaging range of the plurality of magnetic resonance thin slices combined along the thin slice combination direction / thickness direction is greater than or equal to the imaging range of the target magnetic resonance slice.

4. The method according to claim 1, wherein Before sequentially applying a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices to obtain an echo signal corresponding to each of the magnetic resonance thin slices, the method further includes: At least one auxiliary pulse of a target frequency is applied to each of the magnetic resonance slices; the spectrum range of the target frequency deviates from the center frequency of the magnetic resonance imaging system.

5. The method according to claim 2 or 3, characterized in that Imaging the echo signals corresponding to the magnetic resonance thin slices to obtain magnetic resonance sub-images corresponding to the magnetic resonance thin slices includes: using radio frequency pulses to simultaneously excite two magnetic resonance thin layers in each of the magnetic resonance thin layers; Simultaneously, different phase modulations are applied to two magnetic resonance thin slices along the phase encoding direction to obtain K-space data; The K-space data is reconstructed to obtain magnetic resonance sub-images corresponding to each magnetic resonance thin layer.

6. A magnetic resonance imaging method, characterized in that: The method comprises: obtaining a scout image of the scanned object; Selecting a range to be scanned on the scout image; the range to be scanned includes a plurality of target magnetic resonance slices; For each target MRI slice: Applying a scanning sequence multiple times to obtain multiple magnetic resonance sub-images; wherein each magnetic resonance sub-image corresponds to a thin layer of the target magnetic resonance slice, and the thickness of each thin layer combined is greater than or equal to the thickness of the target magnetic resonance slice; the thickness of each thin layer is determined based on the thickness of the target magnetic resonance slice and a gradient threshold; the scanning sequence includes a slice selection gradient, a phase encoding gradient, a readout gradient, and a compensation gradient applied simultaneously with the readout gradient; The multiple magnetic resonance sub-images are weighted to obtain a magnetic resonance image of each target magnetic resonance slice.

7. The method according to claim 6, characterized in that The method further comprises: Before applying the scanning sequence, one or more auxiliary pulses are applied to each target magnetic resonance slice; the frequency of the auxiliary pulses is higher than the frequency of the radio frequency pulses or lower than the frequency of the radio frequency pulses.

8. A magnetic resonance imaging apparatus, characterized in that: The device comprises: a setting module, configured to set a plurality of magnetic resonance thin slices according to a target magnetic resonance slice, wherein a thickness of the plurality of magnetic resonance thin slices after combination is greater than or equal to a thickness of the target magnetic resonance slice, and the thickness of each magnetic resonance thin slice is determined according to the thickness of the target magnetic resonance slice and a gradient threshold; an acquisition module, configured to sequentially apply a slice selection gradient, a phase encoding gradient, and a readout gradient to each of the magnetic resonance thin slices, and simultaneously apply an additional compensation gradient in the slice selection direction of each of the magnetic resonance thin slices while applying the readout gradient, to obtain an echo signal corresponding to each of the magnetic resonance thin slices; The imaging module is used to obtain a target magnetic resonance image according to the echo signals corresponding to each of the magnetic resonance thin slices.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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